, its elevation in the andes gives it a mild climate. and you have aibrantery and somtourist economy.ings on the surrounding hillsides, adequate rainfall and fertile volcanic soils sustain agriculture. but the same natural forces that sustain the economy are also a source of danger. hoping to avoid a tragedy, geographer patty mothes maps and monitors several volcanoes for ecuador's geophysical institute, inclu tungurahua. she is looking for any changes that might signal an eruption. moes and one of these ways thate dohat is to put a prism that's highly reflective, or a number of prisms up on the flanks of the volcano, and then, shooting with this very high-powered laser beam... narrator: the beams reflect off the prisms and back to patty's measuring device. it can detsubthangesin t shap, changes that may forecast an eruption and save lives. their concern is based on history. inside a church, a mural recalls a deadly eruption in 1773. it happened again in 1886 and 1918. so why do people live in such a dangerous place? some people simply cannot afford to move, due to limited economic means.